Al Gietzen wrote:

Al Gietzen wrote:

Any know where I might find a replacement 3/8 double-V pulley in 2

3/4"

or 3" diameter;  to fit a Mitsubishi alternator?

Al

Don't have my cowl off so couldn't measure it but it sounds like you

are

describing the Racing Beat double sheave alternator (PN 11479).

Reduces

alternator rpm 20%.

Tracy Crook

Thanks for the tip, Tracy.  I got the pulley; it is 75mm o.d. (2.95"),
just what I was looking for.  My main reason for changing pulleys was
that I decided to remove the smog pump (vacuum source) and go all
electric; and wanted to still have 2 belts driving the water pump.
While at it, seemed a good idea the slow down the alternator a bit.
E-shaft pulley is 115 mm, old single pulley was 60 mm; speed ratio -
1.92.  That's about 10,000 revs on the alternator at cruise; and maybe
close to 12,000 at max rpm.   The alternator should be able to take
those speeds, but definitely beyond what's needed for supplying power.
New pulley will make it just under 8000 at cruise, and still charge just
fine on the taxiway.

While at it, I made the mod to my  Mitsubishi alternator per Paul
Messinger's article in Contact! Issue 46.  I took the simpler route; use
the built in voltage regulator, but break the connection to the internal
field supply so I can use external over-voltage protection.  I'm sure
the external, linear regulator with OV protection is the ultimate, but
at $228 (Aeroelectric Connection) not worth it.  Main issue is to remove
the potential for runaway voltage failure (however remote) that could do
serious damage to the electrical system.  The surgery on the alternator
was relatively simple - I'd be happy to detail the experience further
for anyone interested.  alventures@msn.com

Al Gietzen

I am interested Al

Paul Lamar

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